1) Field of Invention
This invention relates to Resonant Macrosonic Synthesis (RMS) resonators which are either pulse combustion driven or thermoacoustically driven for the purpose of energy conversion, having specific applications to electric power production.
2) Description of Related Art
History reveals a rich variety of technologies conceived for the purpose of electric power production. Of particular interest are those technologies designed to combust liquid or gaseous fuels in order to produce electric power.
Many types of internal combustion engines have been employed which convert the chemical potential energy of fuels into mechanical energy which is used to drive an electric alternator. However, internal combustion engines need frequent periodic maintenance and provide low conversion efficiencies. Currently, turbines provide the most efficient conversion of fuels, such as natural gas, into electric power. The design and manufacturing sophistication which is inherent in turbine technology can be seen in both their initial cost and operating cost.
Some effort has been directed to the field of standing acoustic waves as a means of electric power production. For example, it was suggested by Swift that the oscillating pressure of thermoacoustically driven standing waves could be utilized for driving an alternator to produce electric power (G. W. Swift, "Thermoacoustic Engines," J. Acoust. Soc. Am. 84, 1166 (1988)). This would be accomplished by coupling a piston to an open end of the acoustic resonator and allowing the vibrating piston to drive a linear alternator The piston would require a gas seal such as a diaphragm or bellows which raises issues of reliability. Moving pistons also limit the dynamic force which can be extracted from the standing wave, thereby limiting the thermoacoustic generator's efficiency.
Another application of standing acoustic waves to the production of electric power was reported by Swift which exploited Magneto Hydrodynamic effects in a thermoacoustically driven liquid sodium standing wave engine (G. W. Swift, "Thermoacoustic Engines," J. Acoust. Soc. Am. 84, 1169 (1988)).
Pulse combustion (PC) is a further field of research where electric power production has been proposed in connection with standing acoustic waves. Other than Magneto Hydrodynamics the PC field has apparently received little attention as a means of producing electric power. Considerable research and development has occurred in the PC field dating back to the previous century. In the early 1920s pulse combustors first received attention as a means to drive electric power producing turbines as seen in U.S. Pat. No. 1,329,559 to Nikola Tesla. Most of the applications research performed today relates to producing either heat or propulsive thrust. For these applications, pulse combustors have always been comparatively attractive, due to their self-sustaining combustion cycle, inherent simplicity, and low production of pollutants. Putnam, Belles, and Kentfield provide a comprehensive history of pulse combustor development showing many of the embodiments and applications in the art of pulse combustion (A. A. Putnam, F. E. Belles, and J. A. C. Kentfield, "Pulse Combustion," Prog. Energy Combust. Sci. 12, 43-79 (1986)). The field of PC research is very active with significant efforts taking place at institutions such as the Gas Research Institute, Sandia Combustion Labs, and various universities.
In summary, thermoacoustic engines have been proposed as a means of driving piston-actuated electric alternators to produce electric power.
However, the concept is in need of certain optimizations, practical improvements, and simplifications. Little effort has been directed toward developing a practical system for utilizing PC-driven standing waves as a means of electric power production. When compared to contemporary technologies, such as gas turbines, a PC electric power generator would provide a fuel-to-electric conversion system of extraordinary simplicity.